Nanotech researchers have constructed a UV laser that they expect will eventually be able to manipulate and precisely deposit Group III and Group V atoms to construct composite materials atom-by-atom. From nanotechweb.org, written by Jacqueline Hewett (requires free registration) “UV laser builds structures atom-by-atom“:

A laser system emitting at 326 nm could be ideal for manipulating Group three atoms such as indium (In), say researchers from the University of Bonn in Germany. The source looks particularly promising for atomic nanofabrication (ANF), an application involving the precise handling and direct deposition of atoms using laser light.

We are experimenting with a laser-cooled In atomic beam,” researcher Jae-Ihn Kim from Bonn’s Institute of Applied Physics told optics.org. “The goal of our research is to generate a fully 3D structured (In,Al)As crystal with periodically modulated In concentration. It is conceivable to generate fully 3D nanostructures with ANF.”

While the potential of ANF is clear, it relies on the availability of lasers emitting at the short ultraviolet wavelengths that match the transitions found in group three atoms. Indium, for example, has a transition at 325.6 nm. This is where Kim and his colleague Dieter Meschede come in with their fibre-based source that frequency triples 977 nm light to 326 nm.

…With a practical 326 nm source in place, Kim has several goals. “In the short term, an indium atomic beam will be laser collimated to enhance the beam flux and reduce the transverse velocity of indium atoms in the beam, which is the requirement to generate narrow structures,” he said. “In the long term, a source of single indium atoms may be constructed to generate structures more accurately on an atom-by-atom basis.”

Kim and Meschede also plan to extend the ANF technique to Group five elements, with a view to creating novel composite materials.